Power compounder

ABSTRACT

A power compounder system and method is disclosed, wherein the system includes a prime mover producing waste heat and a power compounder coupled to the prime mover. The power compounder includes a. working fluid configured to receive thermal energy from the waste heat, a working fluid collector to hold the working fluid, an evaporator fluidly coupled to the working fluid collector for transferring the waste heat to the working fluid to change the working fluid to a vapor working fluid, a feed pump to cause the working fluid to flow between the working fluid collector and the evaporator, a double screw expander fluidly coupled to the evaporator to receive the vapor working fluid to create rotational mechanical energy, where the double screw expander is associated with the prime mover via at least one of a mechanical clutch, an electrical clutch and a sprag clutch.

RELATED APPLICATIONS

This application is a Continuation-in-Parts application of U.S. patentapplication Ser. No. 11/656,309 filed on Jan. 19, 2007 and entitled“Power Compounder” and claims priority to Provisional Patent ApplicationNo. 60/760,633, entitled “Power Compounder” filed on Jan. 19, 2006, thecontents of both of which are incorporated herein by reference in theirentireties.

BACKGROUND

The conversion of fuels into electricity has long been the focus ofengineers. The supply of the fuel to a generation site, as well as thereliability and cost of the supply, is factored into the engineeringdecision process.

The thrust of waste heat recovery technology is to make use of thermalenergy normally discarded from a primary power conversion process. Inmany prior art devices, the discarded thermal energy (i.e., waste heat)is harnessed to drive additional thermo-fluid processes that can yieldadditional energy (i.e., electricity).

Referring to prior art FIG. 1, the prior art waste heat recovery systemdirects a supply of waste heat measured at temperatures between 300° F.to 800° F. from a heat source to an evaporator (see numeral 1). Thewaste heat is transferred to a working fluid in the evaporator. Theworking fluid is evaporated; changes from a liquid to a vapor, in theevaporator and is expanded through a turbine (see numeral 2). Theexpansion of the working fluid through the turbine drives the turbine.The turbine, in turn, drives an electric generator coupled to theturbine. The generator produces electrical power. The working fluidflows to a condenser and changes phase from vapor to a liquid (seenumeral 3). The liquid working fluid is then pumped back to theevaporator and begins the cycle again (see numeral 4). The abovedescribed system employs a closed-loop Organic Rankine Cycle to produceelectricity from a thermal energy source, such as waste heat. Thisexample illustrates that the prior art waste heat recovery systems wereutilized to produce electricity.

Using the above concept of a reverse refrigeration cycle, either aRankine Cycle or Organic Rankine Cycle (ORC), the waste heat of anengine can be converted to produce a more efficient engine; notelectricity. However, the above example relies on turbines to operatethe generator. Turbines operate at a greater rotational speed thanconventional engines and require extensive, complex machinery in orderto try and capture the thermal energy for reuse as mechanical energy.

What is needed in the art is a Rankine Cycle or an Organic Rankine Cyclesystem to convert waste heat from an engine into useful power for theengine that is simple, reliable and cost effective.

SUMMARY

The following presents a simplified summary of the present disclosure inorder to provide a basic understanding of some aspects of the presentdisclosure. This summary is not an extensive overview of the presentdisclosure. It is not intended to identify key or critical elements ofthe present disclosure or to delineate the scope of the presentdisclosure. Its sole purpose is to present some concepts of the presentdisclosure in a simplified form as a prelude to the more detaileddescription that is presented herein.

A power compounder is disclosed. The power compounder comprises aworking fluid configured to receive thermal energy from waste heat of aprime mover, a working fluid collector, an evaporator configured totransfer waste heat to a working fluid producing a phase change to vapor(or gas) in the working fluid, a double screw expander configured toreceive the working fluid for creating rotational mechanical energy, anda condenser configured to produce another phase change in the workingfluid to liquid. The double screw expander transfers the rotationalmechanical energy via a shaft to the prime mover.

The disclosure is also directed toward a power compounder system. Thepower compounder system comprises a prime mover producing waste heat anda power compounder coupled to the prime mover. The power compoundercomprises a working fluid configured to receive thermal energy from thewaste heat from the prime mover; a working fluid collector configured tohold the working fluid as a liquid working fluid; an evaporator fluidlycoupled to the working fluid collector, such that the evaporator isconfigured to transfer the waste heat to the working fluid to change theworking fluid from a liquid working fluid to a vapor working fluid; adouble screw expander fluidly coupled to the evaporator, such that theexpander is configured to receive the vapor working fluid to createrotational mechanical energy from expansion of the vapor working fluidthrough the double screw expander, the double screw expander transfersthe rotational mechanical energy via a shaft to the prime mover; and acondenser fluidly coupled to the double screw expander, such that thecondenser is configured to receive the vapor working fluid and changethe vapor working fluid to the liquid working fluid, the condenser isfluidly coupled to the working fluid collector.

The disclosure is also directed toward a method of using a powercompounder system. The method comprises directing waste heat produced ina prime mover to a power compounder; transferring thermal energy fromthe waste heat to a liquid working fluid; transforming the liquidworking fluid to a vapor working fluid in an evaporator; directing thevapor working fluid through a double screw expander fluidly coupled tothe evaporator; creating rotational mechanical energy in the doublescrew expander when the vapor working fluid flows through the doublescrew expander; transferring the rotational mechanical energy via ashaft of the double screw expander to the prime mover; and directing thevapor working fluid to a condenser for transforming to the liquidworking fluid, the condenser is fluidly coupled to the expander.

A power compounder system is provided and includes a prime moverproducing waste heat and a power compounder coupled to the prime mover.The power compounder includes a working fluid configured to receivethermal energy from the waste heat from the prime' mover, a workingfluid collector configured to hold the working fluid as a liquid workingfluid, an evaporator fluidly coupled to the working fluid collector, theevaporator configured to transfer the waste heat to the working fluid tochange the working fluid from the liquid working fluid to a vaporworking fluid, a feed pump configured to cause the working fluid to flowbetween the working fluid collector and the evaporator and a doublescrew expander fluidly coupled to the evaporator, wherein the expanderis configured to receive the vapor working fluid to create rotationalmechanical energy from expansion of the vapor working fluid through thedouble screw expander, such that the double screw expander transfers therotational mechanical energy via a shaft to the prime mover. The doublescrew expander is further coupled to the prime mover via at least one ofa mechanical clutch, an electrical clutch and a sprag clutch. The powercompounder further includes a condenser fluidly coupled to the doublescrew expander, wherein the condenser is configured to receive the vaporworking fluid and change the vapor working fluid to the liquid workingfluid, wherein the condenser is fluidly coupled to the working fluidcollector.

A method of using a power compounder system is provided and includesdirecting waste heat produced in a prime mover to a power compounder,transferring thermal energy from the waste heat to a liquid workingfluid, transforming the liquid working fluid to a vapor working fluid inan evaporator, directing the vapor working fluid through a double screwexpander fluidly coupled to the evaporator, wherein the double screwexpander is further coupled to the prime mover via at least one of amechanical clutch, an electrical clutch and a sprag clutch, creatingrotational mechanical energy in the double screw expander when the vaporworking fluid flows through the double screw expander, transferring therotational mechanical energy via a shaft of the double screw expander tothe prime mover and directing the vapor working fluid to a condenser fortransforming to the liquid working fluid, wherein the condenser isfluidly coupled to the expander.

BRIEF DESCRIPTION OF THE FIGURES

Referring now to the figures, wherein like elements are numbered alike:

FIG. 1 is a diagram of a prior art waste heat recovery system;

FIG. 2 is a schematic of an exemplary power compounder system;

FIG. 3 is a side view of an exemplary power compounder system;

FIG. 4 is another side view of the exemplary power compounder system ofFIG. 3;

FIG. 5 is a side view of another exemplary power compounder system;

FIG. 6 is a bottom view of a double screw expander;

FIG. 7 is a front view of a double screw expander;

FIG. 8 is a front view of a profile of the rotors of a double screwexpander;

FIG. 9 is a front view of another profile of the rotors of a doublescrew expander;

FIG. 10 is a side isometric view illustrating a clutch device beingemployed between the expander and a prime mover; and

FIG. 11 is a side isometric view of illustrating a clutch device beingemployed between a pump and the expander.

DETAILED DESCRIPTION

Persons of ordinary skill in the art will realize that the followingdisclosure is illustrative only and not in any way limiting. Otherembodiments of the disclosure will readily suggest themselves to suchskilled persons having the benefit of this disclosure.

The present disclosure is a power compounder system that converts wasteheat thermal energy from a source (or prime mover or engine) intorotational mechanical energy. Power compounding is the process ofdirectly attaching an expander (or a compressor configured to act as anexpander) to a shaft of a prime mover. For example, in a typicalcombustion engine, the thermal energy is normally discarded via jacketwater heat through a radiator, engine exhaust out a stack, oil cooler,or any other conventional means. In the present disclosure, the normallydiscarded waste heat is recovered from the engine and harnessed. Thewaste heat is harnessed using either a Rankine Cycle or an OrganicRankine Cycle (ORC) power compounder having an expander (i.e., double ortwin screw). The waste heat is harnessed by conversion to rotationalmechanical energy which is redirected back to the engine, increasing theengine's net power output by as much as about 10% additional horsepower.This additional horsepower is achieved without using additional fuel orproducing additional emissions.

FIG. 2 is a schematic of an embodiment of the present disclosure. FIGS.3, 4, and 5 illustrate exemplary embodiments of the power compounder 10system coupled to a prime mover (e.g., an engine) 12. The powercompounder 10 has an expander 14 that is coupled to the prime mover 12via a shaft 16. In one embodiment illustrated in FIGS. 3 and 4, elements(i.e., the evaporator 18, the condenser 20, and the like) of the powercompounder 10 are contained within a system cabinet 22.

Although a combustion engine is illustrated in FIGS. 3, 4, and 5 as theprime mover 12, any machine that utilizes mechanical energy can beutilized, including but not limited to, pumps, external combustionengines, internal combustion engines, turbines, compressors, and thelike.

Referring again to FIG. 2, as the prime mover 12 is operated, waste heat(illustrated as arrow 24) is discarded from the prime mover 12. Thewaste heat 24 can be transferred via any known means compatible to theprime mover, including but not limited to, engine lube oil, coolant,exhaust, water jacket, and the like. Waste heat is a term that generallycovers various sources of thermal energy in a transfer medium attemperatures as low as about 140° F. (such as a fluid, a hot gas, hotoil, hot water, steam, and the like). The waste heat can be suppliedfrom a wide variety of sources including but not limited to: internalcombustion engines, gas turbines, gas flares in landfills, industrialmanufacturing processes that continuously produce thermal energy,incinerators, boilers, water heaters, geothermal wells, methane, bio-gassources, and the like.

In the preferred embodiment, waste heat 24 is directed from the primemover 12 to the power compounder 10 via an outlet 26. The thermal energy28 is transferred to a working fluid (illustrated as arrow 30) in theevaporator 18. The waste heat 24 medium is returned to the prime mover12 via inlet 27. The working fluid 30 can be any known working fluid,including but not limited to, water, refrigerants, light hydrocarbons,and the like. The working fluid must be compatible with the powercompounder system. Examples of refrigerants include but are not limitedto, R-124, R-134a, R-245fa, and the like. The working fluid 30 istransformed in an evaporator 18 located in the system cabinet 22. Theevaporator 18 transfers the thermal energy 28 from the waste heat 24from the prime mover 12 to the working fluid 30.

The evaporator 18 exchanges the thermal energy 28 from the waste heat 24to the working fluid 30. The evaporator 18 can be any variety of heatexchangers and fashioned to operate with the waste heat, including, butnot limited to, plate, tube and shell, tube and fin, and the like. Forexample, if the waste heat is in the form of an internal combustionengine exhaust, the heat exchanger can comprise a gas heat exchanger.Intermediate heat exchangers (not shown) can be employed to separate thewaste heat medium from the evaporator.

The working fluid 30 is heated in the evaporator 18 and changes phasefrom a liquid phase to a vapor (or gas) phase. The working fluid 30having gained the thermal energy 28 and having reached a higher energystate (i.e., vapor or gas phase), flows from the evaporator 18 throughpiping 32 to the expander 14, and expands through the expander 14transferring the higher thermal energy into mechanical energy. Theworking fluid 30 is compressed (i.e., under pressure) having potentialenergy as it enters the expander 14 through the inlet 46. Afterproceeding through the expander 14, the working fluid exits through theoutlet 48 having transferred the potential energy to the shaft 16creating kinetic energy.

In a preferred embodiment, the shaft 16 of the expander 14 can becoupled directly to a drive shaft of the prime mover 12 through agenerator (see FIG. 5) or coupled with belts 34 and/or gears or pulleys36, 38 to the crankshaft 40 (or drive shaft or any other appropriatelocation) of the prime mover 12 (see FIGS. 3 and 4). The shaft 16 of theexpander 14 can also be connected via a pulley and idler arrangement (ordirectly in the case of the engine's power take-off (PTO) shaft) (notshown) to the output shaft of the prime mover 12 itself.

The preferred expander 14 is a double (or twin) screw expander 32. FIG.6 illustrates a bottom view of an interior of a double screw expander32. The double screw expander 32 uses the working fluid 30 to createmechanical rotation. The working fluid 30 expands through the doublescrew expander 32 causing the two rotors (or screws) 34, 36 to turn (orrotate), thus creating mechanical energy. The mechanical energy istransferred into shaft power. Referring now to FIG. 7, a front view of adouble screw expander 32 is illustrated. The working fluid 30 flows intothe double screw expander 32 via inlet 46 and exits via outlet 48. Asthe working fluid 30 expands through the double screw expander 32,mechanical energy is created. The mechanical energy is then transferredinto shaft power.

A double screw expander 32 has two meshing helical rotors 34, 36 thatare contained within a casing 42, which surrounds the rotors 34, 36 witha very small clearance. The spaces between the rotors 34, 36 and thecasing 42 create working chambers 44. The working fluid 30 enters thedouble screw expander 32 through inlet 46 and expands through theworking chambers 44 in the direction of rotation until it is expelledthrough outlet 48. Power is transferred between the working fluid 30 andthe shaft 16 from torque created by the forces on the rotor 34, 36surfaces due to the pressure of the working fluid 30, which changes withthe volume of the working fluid 30.

In order to achieve a high flow rate and efficiency, the profile of therotor 34, 36 is important. A conventional profile is illustrated in FIG.8, in which a symmetric profile of the rotors 34, 36 is provided. Thepreferred embodiment for the double screw expander 32 profile isillustrated in FIG. 9. A rack generated “N” profile utilized as a rotorprofile increases the rotational speed of the double screw expander 32.

Referring again to FIGS. 2 and 3, upon exiting the expander 14 throughthe outlet 48 to piping 50, the working fluid 30 is now a low pressuregas (or vapor) that flows to a condenser 20, where the working fluid 30undergoes a phase change again from vapor (or gas) to liquid. In apreferred embodiment, the condenser 20 comprises at least one of shells,tubes, and fins. The use of a refrigerant, cooling water, or cooling aircan enhance the cooling capabilities of the condenser 20.

In still yet another embodiment, referring to FIG. 10 and FIG. 11, theshaft 62 of the expander 32 (such as a double screw expander) is coupledto the shaft 64 of another device, such as the prime mover 12 or a pump12B (see FIG. 11) via a clutch device 60, such as a mechanical clutch,an electrical clutch and/or a sprag clutch (non-reversible and/orreversible), wherein the clutch device 60 can be used to disengage theshaft 62 of the expander 32 from the shaft 64 of the prime mover 12 tolower the revolutions per minute (RPM) of the expander 32. Simply put aclutch is a device that can be engaged or disengaged to transmit/removerotational forces of a rotating shaft and is particularly useful inmechanisms that include two or more rotating shafts where it isdesirable to selectively transmit the motion of one shaft to anothershaft. As is known, there are many different types of clutches. One typeof clutch, for example, is the “Sprag” clutch which is a one-wayoverrunning (or freewheel) clutch that can be used to disengage adriveshaft from a driven shaft as desired. A Sprag clutch typicallyincludes a cylindrical inner race surrounded by a cylindrical outer racewith an annular space therebetween and is particularly useful when twoor more motors can be used to drive the same mechanism or when thedisengagement of one motor is desired. The use of a sprag clutch isadvantageous in different situations where it is desirable to lower therevolutions per minute (RPM) of the shaft of the expander 32. Forexample, when the prime mover 12 (or pump 12B) is sitting idle or whenthe prime mover 12 is not generating enough heat, it may desirable tolower the RPM's of the shaft 62 of the expander 32 to prevent theexpander 32 from being damaged (i.e. burning out). This may beaccomplished by engaging the clutch device 60 to allow the shaft 62 ofthe expander 32 to slow its rotation. When the prime mover 12 isgenerating a sufficient amount of waste heat, the clutch device 60 maybe disengaged to allow the rotation of the shaft 62 of the expander 32to increase.

It should be appreciated that the clutch device 60 may be controlled viaany device and/or method suitable to the desired end purpose, such as anelectrical switch, a mechanical switch and/or an electromechanicalswitch. It is contemplated that a sensing device and a controller devicemay be included in the power compounder system 10, wherein the sensingdevice and a controller device are communicated with each other and thepower compounder system 10 to monitor various desired parameters of thepower compounder system 10, such as the expander 32 and/or prime mover12 (and/or pump 12B). The sensing device may monitor various parametersof the power compounder system 10 as desired, such as the waste heatfrom the prime mover 12 and/or the rotation speed of the shaft 62 of theexpander 32 and/or the shaft 64 of the prime mover 12 and communicatethese parameters to the controller device. The controller device maythen control the clutch device 60 to engage and/or disengage the shaft62 of the expander 32 from the rest of the system (i.e. prime mover 12)responsive to the parameters received from the sensing device. It isalso contemplated that the controller may send instructions to thesensing device to configure which parameters the sensing device willsense. It is further contemplated that the sensing device and/or thecontroller may be communicated with a computing device (a local deviceand/or a remote device) to allow a third party to monitor the powercompounder system 10 and/or control the clutch device 60 as desired. Itis further contemplated that all communications may be accomplished viawired and/or wireless communications.

It should be appreciated that as used herein, working fluids include anytype of working fluid suitable to the desired end purpose, such aswater, steam and/or organics (including, but not limited to refrigerantsand/or hydrocarbons).

The liquid working fluid 30 then flows by gravity to a receiver tank 52configured to contain the liquid working fluid 30 (i.e., preferably atank that is about 30 gallons to about 100 gallons). A feed pump 54controls the flow rate of the working fluid 30 to the evaporator 18. Acooling medium, such as liquid or air, can be utilized to furthercondense the gaseous working fluid into a liquid working fluid. Asillustrated in FIG. 2, a cooling tower 56 (or cooling fan, and the like)can be utilized to supply the cooling medium.

The admission of wet vapor to the expander 14 can be used to improve theperformance of the power compounder 10 by simplifying and reducing thecost of expander 14 lubrication by dissolving or otherwise dispersingabout 5% oil by mass in the working fluid 30.

The above system is a closed loop Rankine Cycle, employing water as theworking fluid, or an Organic Rankine Cycle, using refrigerants or lighthydrocarbons as the working fluid, or some combination thereof, in orderto produce rotational mechanical power from thermal energy sources. Thisuse of a power compounder results in an increase of net power to thehost prime mover of about 5% to about 15% net power, with about 10% netpower preferred.

The present disclosure includes a simple and reliable cost efficientpower compounder system, either a Rankine Cycle or an Organic RankineCycle, using a double screw expander to produce rotational power. Thisrotational mechanical energy can be used to increase power output by asmuch as about 10% net increase to many prime movers, such as engines,pumps and mechanical power outputs for hundred of applications. Sincethe rotational speed of the expander of the power compounder is operatedat similar rotational speeds as the prime mover, there is no need forany high speed reduction gear reducer or electronics. The rotationalmechanical energy of the expander can be synchronized to the rotation ofthe prime mover.

While the disclosure has been described with reference to an exemplaryembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the disclosure. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings without departing from the essential scopethereof Therefore, it is intended that the disclosure not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this disclosure.

1. A power compounder system comprising: a prime mover producing wasteheat; and a power compounder coupled_to said prime mover, said powercompounder comprising: a working fluid configured to receive thermalenergy from said waste heat from said prime mover; a working fluidcollector configured to hold said working fluid as a liquid workingfluid; an evaporator fluidly coupled to said working fluid collector,said evaporator configured to transfer said waste heat to said workingfluid to change said working fluid from said liquid working fluid to avapor working fluid; a feed pump configured to cause said working fluidto flow between said working fluid collector and said evaporator; adouble screw expander fluidly coupled to said evaporator, said expanderconfigured to receive said vapor working fluid to create rotationalmechanical energy from expansion of said vapor working fluid throughsaid double screw expander, said double screw expander transfers saidrotational mechanical energy via a shaft to said prime mover, whereinsaid double screw expander is further coupled to said prime mover via atleast one of a mechanical clutch, an electrical clutch and a spragclutch; and a condenser fluidly coupled to said double screw expander,said condenser configured to receive said vapor working fluid and changesaid vapor working fluid to said liquid working fluid, wherein saidcondenser is fluidly coupled to said working fluid collector.
 2. Thepower compounder system of claim 1, wherein said prime mover has anincrease of net power of about 10% from addition of said rotationalmechanical energy.
 3. The power compounder system of claim 1, whereinsaid working fluid flows by force of gravity from said condenser to saidworking fluid collector.
 4. The power compounder system of claim 1,wherein said feed pump is configured to control a flow rate of saidworking fluid from said working fluid collector to said evaporator. 5.The power compounder system of claim 1, further comprising: a pumpconfigured to supply said working fluid to said evaporator.
 6. The powercompounder system of claim 1, wherein said prime mover is selected fromthe group consisting of engines, pumps, external combustion engines,internal combustion engines, turbines, and compressors.
 7. The powercompounder system of claim 1, wherein said rotational mechanical energyis synchronized to a rotational mechanical energy of said prime mover.8. The power compounder system of claim 1, further comprising: a timingbelt coupled to a pulley on said double screw expander and to a pulleyon said prime mover, wherein a combination of said timing belt and saidpulleys transfers said rotational mechanical energy to said prime mover.9. The power compounder system of claim 1, further comprising: a systemcabinet comprising said working fluid collector, said evaporator, saidcondenser and a cooling tower coupled to said condenser.
 10. A method ofusing a power compounder system, comprising: directing waste heatproduced in a prime mover to a power compounder; transferring thermalenergy from said waste heat to a liquid working fluid; transforming saidliquid working fluid to a vapor working fluid in an evaporator;directing said vapor working fluid through a double screw expanderfluidly coupled to said evaporator, wherein said double screw expanderis further coupled to said prime mover via a belt, powered take-offshaft and at least one of a mechanical clutch, an electrical clutch anda sprag clutch; creating rotational mechanical energy in said doublescrew expander when said vapor working fluid flows through said doublescrew expander; transferring said rotational mechanical energy via ashaft of said double screw expander to said prime mover; and directingsaid vapor working fluid to a condenser for transforming to said liquidworking fluid, said condenser fluidly coupled to said expander.
 11. Themethod of claim 10, further comprising: increasing a net power of saidprime mover by about 10%.
 12. The method of claim 10, furthercomprising: flowing said working fluid by force of gravity from saidcondenser to a working fluid collector fluidly coupled to saidevaporator; and controlling a flow rate of said working fluid from saidworking fluid collector to said evaporator using a feed pump.
 13. Themethod of claim 10, further comprising: supplying said working fluid tosaid evaporator using a pump.
 14. The method of claim 10, wherein saidprime mover is selected from the group consisting of engines, pumps,external combustion engines, internal combustion engines, turbines, andcompressors.
 15. The method of claim 10, further comprising:synchronizing said rotational mechanical energy of said power compounderto a rotational mechanical energy of said prime mover.
 16. The method ofclaim 10, further comprising: coupling a timing belt to a pulley on saiddouble screw expander and to a pulley on said prime mover, wherein acombination of said timing belt and said pulleys transfers saidrotational mechanical energy to said prime mover.
 17. The method ofclaim 10, further comprising: coupling a timing belt to a gear on saiddouble screw expander and to a gear on said prime mover, wherein acombination of said timing belt and said gears transfers said rotationalmechanical energy to said prime mover.
 18. The method of claim 10,further comprising: positioning a working fluid collector, saidevaporator, said condenser and a cooling tower in a system cabinet, saidcooling tower coupled to said condenser.